Normally, in display devices such as a television receiver, display states such as the contrast of a screen can be adjusted by users as desired.
Meanwhile, in retail stores and so on, the display state of the screen of the display device is preferably set in a given state in order to present the full extent of characteristics and appeal of the product to customers.
Therefore, a display device capable of switching between an operation mode set for household use (hereinafter referred to as a normal mode) and an operation mode set for use in retail stores and so on (hereinafter referred to as a storefront mode) has been proposed (see Patent Document 1, for example).
In the normal mode, when the display state of the screen of the display device is changed by users, the changed state is maintained.
On the other hand, in the storefront mode, the display mode of the screen is returned to the given state that is appropriate for storefront display whenever a predetermined time period elapses.
In this case, the display state of the screen is automatically returned to the appropriate given state after the elapse of the predetermined time period even if the display state of the screen of the display device on exhibit is changed to an undesirable state by customers.    [Patent Document 1] JP 2006-238255 A